Production of dicyclic olefins and derivatives



Unied States Patent PRODUCTION OF DICYCLIC OLEFINS AND DERIVATIVESClaims. c1. 260- 666) This invention relates to a method fortransforming a tertiary chloride of an alkyl cyclopentane into dicyclicchlorides which can be dehydrochlorinated .to useful dicyclic olefinsthat on selective dehydrogenation become converted mainly to aromatichydrocarbon derivatives, more particularly alkyl naphthalenes.

In brief, the process of the present invention is. concerned with thefollowing reaction steps:

(1) The formation of dicyclic chlorides from tertiary chlorides ofcyclopentanes, more particularly as they are formed in reacting an alkylcycloalkane with a tertiary alkyl chloride in the presence of strongsulfuric acid.

(2) Dehydrochlorination of the dicyclic chlorides to produce dicyclicolefins and hydrogen chloride.

(3) Selective dehydrogenation of the dicyclic olefins to form aromatichydrocarbon derivatives;

This invention is based upon the discovery that in the presence ofstrong sulfuric acid as catalyst two molecules of a tertiarychloro-alkyl cyclopentane condense to produce one molecule of dicyclicchlorides and one molecule of hydrogen chloride. Thus withl-chloro-l-methylcyclopentane, for example, the reaction can be writtenas follows:

dicyclic chlorides H01 Since in this condensation step the cyclopentanering is simultaneously isomerized producing to a major extent compoundscontaining a fused ring structure, such as chloro-dimethyldecalins.whenemploying l-chloro-l-methylcyclopentane, it is thus possible, forexample, to dehydrochlorinate the dicyclic chloride to dicyclic olefinswhich on selective dehydrogenation become converted toalkylnaphthalenes. It is of course understood that the di cyclicchlorides and particularly the dicyclic olefins can besubjectedto'various reactions for producing desired final products.Forexample, the dicyclic olefins may be oxonated or oxidized to formdibasic acids. They may be chlorinated to obtain chlorides which areuseful in insecticide and fungicide compositions.

.The tertiary chloro-cyclopentanes can be produced using any knownprocedure, such as the addition of hydrogen chloride-to a tertiaryalkyl-cyclopentene. The chlorination of a saturated alkylcyclopentane orthereaction of a tertiary cyclopentanol with hydrogen chloride can alsobe employed. 4

An alternate procedure for "the production of tertiary 2,810,001 lfatented Oct. 15, 1957 chloro-cyclopentanes, which'utilizes readily availablematerials, consists of a selective halogen-hydrogen exchange reactionbetween an alkylcyclopentane and a tertiary chlorohydrocarbon of thealiphatic series. This step is a continuation-in-part of application,Serial Number 156,038, filed April 14, 1950, now abandoned. This methodcan best be illustrated by the following reaction, using for examplemethylcyclopentane as the alkylcyclopentane and tertiary butyl chlorideas the aliphatic tertiary chloro-hydrocarbon:

CHa-CH2 CH2 CH2CH1 CH1 91H: OH: CH3-( JCHZ 1112- Hz CHr-CCH3 C l l l CC1I l Methylcyclopentane+tertiary butylchloride-el-chloro-l-methylcyclopentane+isobutane As is evident fromthis illustration a tertiary chlorobon.

However, under the conditions employed to effect reaction (2) it isgenerally impossible to prevent reaction.

(1) which consists of the condensation of the tertiarychloro-alkylcyclopentane to the dicyclic chlorides, to take place tosome extent. The extent of reaction (1) depends on the contact time andalso on the concentration of'the tertiary chloro-alkylcyclopentane thathas been allowed to build-up in the reaction mixture. Depending on conditions employed varying ratios of tertiary chloroalkyl-- cyclopentanesto dicyclic chlorides can be obtained. However, from the standpoint ofthis invention conditions are:

. chosen which result in the formation of dicyclic chloridesv as thepredominant product.

The steps just described can best be summarized as the formation ofdicyclic chlorides from tertiary chloro-alkyl-- cyclopentanes as theyare formed in reacting an alkylcyclopentane with an aliphatic tertiarychloro-hydro-- carbon.

The conditions for condensing a tertiary chloro-alkyl-- cyclopentaneconsist of contacting the tertiary chloride: with 85-100% sulfuric acidat about -10 to 25 C.,-. preferably 0 to 10 C. The ratio of tertiarychloro-- tween 0.1 to 2 atm. The hydrogen chloride pressure isattainedby making use of the hydrogen chloride evolved in the reaction. saturatethe catalyst and diluent phase with extraneous hydrogen chloride priortothe addition of the tertiary; chloro-methylcyclopentane. I I

To demonstrate the feasibility of this reaction the -re.-.,- sults of arun in which 1-chloro-l-methylcyclopentane 1 was contacted with 96%sulfuric acid are summarized below:

However, it is generally preferred to IABLEJ. Condensation of1-chl0r0-I-methylcyclopentane to dicyclic chlorides i th rega t f..- viw s WWW; acid a l' lue it Ilse-n irat l 9 il en Vol. ratio of 'l chlor96% H2504 0.32 1-chlorol-methylcyclopentane converted, mole percent 62Selectivity to, mole percent:

Dicyclic chlorides (C 1zH21Cl) 52 Dicyclic, hydrocarbons (.C12 H2z) 32Other material not identified 13.5

In a process for preparing dichlorides from teritarychloro-alkylcyclopentanes as they are formed in reacting analkylcyclopentane with a teritary chloro-hydrocarbon of thealiphatic-series, an available, aliphatic tertiary chloride, e. g.,tertiary butyl chloride,is contacted With the alkylcyclopentane, such asmethylor dimethylcyclopentane, in the presence of 85100% sulfuric acidat about l0 to 25 C., preferably0to C. The aliphatic tertiary chloridereactantcan be added all at once or in increments over the entirereaction period. The volume ratio ofalkylcyclopentane/sulfuric acid canvary over'a range from- 10/1 to 1/10, preferably from 2/ 1' to 5/1. Themole ratio ofalkylcyclopentane/aliphatic tertiary chloride can vary from1/ 1 to20/1 ormore. The hydrogenchlor-ide pressure maintained overthereaction mixture is similar to-that disclosed above.

A representative run for producing satisfactoryyields of dicyclicchlorides from methylcyclopentane when reacted with tertiary butylchloride using 96% sulfuricacidas catalyst is tabulated with a comparedrun in which the contact time was shortened toobtaimchieflyagood'yieldof l-chloroal-methylcyclopentane in the following Table II--.

TABLE II Reactionof methylcyclopentane with tert ary butyl chlorzde mthe presenceofconcentrated-sulfuric acid;

Experiment No. 608:3 69 8 11 Conditions of Experiment:

Temperature, C 2 3 Contact Time, Hrs 6' 0.5 Total; pressure on system,p. s. i. g. 1.5 Mole ratio MCyP/tertiary Butyl chloride 2. -l 2. 4 Vol.ratio MCyP+tertiary Bntyl ch1 or ide/9 6%.HrS04 3.5 3. 5.Methylcyclopcntane Converted, Mole perce t--:.. 41.0 (3.57 is 5 (1.58 7moles) moles) Selectivity to, Mole percent:-

L-chloro-l-rnethylcyclopentane. 8,1 38. 5 Dicyclic chloride (CmHnCl) a55, 0 e 38. 6 Dicyclic hydrocarbon (C izHn) l6. 0 6. 5 Alkylated dicylichydrocarbon. 5.5 4. 5 In catalyst layer 9. 6, 9. 0 TertiaryButylOhloride Converted percent 98.0 (3.62; 45 5 (1.61 moles) moles)Selectivity to, Mole percent:

Isobutane 89.7 80. 0 In catalyst layer 5. 4 5.0

Based on dehydrohalogcnation followed by dehydrogenation the dicyolic;chlorideconsists predominantly of chlorodimethyldecalin of free H701 wasproduced. 1.3 moles of chlorine recovered as p d t-- Similar runs weremade with dimethylcyclopentane to produce sizable quantities of'dicyclicchlorides.

The final dicyclic chloride produce is readily dehydrochlorinatedtoproduce the dicyclic olefin bysimply heat: ing'the dicyclicichl'orideto'ternperatur'es above 100 C. Other methods such as, for example,treatment of the dicyclic chloride with alcoholic caustic also bringsabout the dehydrochlorination to term dicyclic olefins. The

producing desired final products as pointed out above.

It is of particular interest to note that the dicyclic olefins, producedin accordance with the described process are readily convertedtoarornatic hydrocarbons. For example, the dimethyloctahydronaphthalenesformed as a principal: dicyclic olefinfrommethylcyclopentane can bedehydrogenated to dimethyl naphthalenes. The dicyclic. olefins, producedfromv thealkyl naphthenes are converted predominantly to aromatichydrocarbons by dehydrogenation over a catalyst and under conditionswhich avoid splitting ofi hydrocarbon groups. This is demonstrated bythedehydrogenation; over platinum supported on activated charcoal at 265 C.The dicyclic olefin used was obtained. by'dehydrochlorination of thedicyclic chloride produced by reacting methylcyclopentane with tertiarybutyl chloride, dehydrogenation conditions and results being tabulatedin the following Table II.

TABLE-III Dehydrogenation of dicyclic olefins oven platinumv on t ated crcealatzdi? C.

Charge 2,7,0 g n. (C zl lao), Recovery;

Liquid 2.40 gm. Gas 9.2;2 litersof Hz atOf I C. and 760 mm. Product:Approx. composition,

Comp ound. mole percent Unconverted dicyclic olefin. 5.5 Hydrogenateddicyclic olefin -Q. 12.5. Phenyl methylcyclopentane, 27.0 Dimethylnaphthalenes 55.0

Based on this breakdown, there should have been. prodnced 9.6 litersdlmethyl napht-halenes, 2 moles Ha/mole phenyl methylcyclo entane andcorrected for thehydrogen consumed in the ydrogenation of. the olefin.Thehydrogen collected contained only aitrace of light-hydrocarbon.

These results clearly demonstrate thatthe dicyclic ole;

fins consist largely of alkyl octahydronaphthalenes. with tion of the.thus formed chloride of the alkylcyclopentane in the presence of thesulfuric acid While maintaining a hydrogen chloride partial pressureoverthe resulting reaetionmixtureat above 0.1 atmosphere until a substantial amount: ofdicyclic chloride is formed, then stopping the reactionand recovering as the reaction product a mixture comprising principallythe dicyclic chloride and a dicyclic hydrocarbon formed by condensationof the chloride of the alkyl; cyclopentane.

2. The process of; forming a dicyclic chloride having the compositionC12Hz1Cl from methylcyclopentane, which comprises reacting a majormolarproportion of methylcyclopentane with tertiary butyl chloride in thepresence of about 96% strength sulfuric acid at a tem perature in therange of 0 to 10 (3., maintaining a partial pressure of about 1.5atmospheres of hydrogen chloride in contact with the reaction mixturewhile continuing reac-. tion of the. reaction mixture until asubstantial amount of product formed is'a dicyclicchloride having thecomposition C12H21Cl then stopping the reaction and recovering a rea tin Pro u mixture Co tainin p n p y said dicyclic chloride and a dicyclichydrocarbon liaving the composition (3121-12 of hydrogen assuming 4moles Hz/mole.

3. In a process of forming dicyclic derivatives the step which comprisescontacting 1-chloro-1-methylcyclopentane with 85-100% sulfuric acid atabout 10-25 C. under a partial pressure of 0.1 to 5 atmospheres of HCluntil a substantial amount of the chloro-methylcyclopentane is convertedto a dicyclic chloride having a composition C12H21Cl. then stopping thereaction and recovering a reaction product mixture containingprincipally said dicyclic chloride and a dicyclic hydrocarbon having thecomposition C12H22.

4. The process of forming dicyclic derivatives from an alkylcyclopentanewhich comprises reacting an alkylcyclopentane with a tertiary alkylchloride in the presence of 85 to 100% sulfuric acid at a temperature ofabout l to 25 C., maintaining the resulting reaction mixture underpartial pressure of 0.1 to atmospheres of hydrogen chloride until asubstantial amount of dicyclic hydrocarbon chloride is formed, heatingthe resulting dicyclic hydrocarbon chloride, removing the evolved HCland recovering a dicyclic olefin.

5. A process for converting alkylcyclopentane to dicyclic aromatichydrocarbon derivatives which comprises converting the alkylcyclopentaneto a dicyclic chloride by reacting the alkylcyclopentane with a tertiaryalkyl chloride in the presence of to H2504 While maintaining theresulting reaction mixture under a partial pressure of 0.1 to 5atmosphere of hydrogen chloride until a substantial amount of dicyclicchloride is formed, dehydrochlorinating the thus formed dicyclicchloride by heating the dicyclic chloride to an elevated temperature,and removing hydrogen chloride evolved therefrom, and contacting theresulting dicyclic olefin with a platinum catalyst at 265 C. toselectively dehydrogenate the resulting dicyclic olefin formed from thedicyclic chloride.

References Cited in the file of this patent UNITED STATES PATENTS1,221,382 Schmidt Apr. 3, 1917 2,396,486 Ballard Mar. 12, 1946 2,443,079Otto June 8, 1948 OTHER REFERENCES Beilstein: Handbuch der OrganischenChemie, vol. 5, 1st Supplement, p. 11.

1. A PROCESS FOR SYNTHESIZING A DICYCLIC COMPOUND FROM ANALKYLCYCLOPENTANE, WHICH COMPRISES REACTING AN ALKYLCYCLOPENTANE WITH ATERTIARY ALKYL CHLORIDE IN THE PRESENCE OF 85 TO 100% SULFURIC ACID AT ATEMPERATURE IN THE RANGE OF ABOUT -10* TO 25*C., AND CONTINUING REACTIONOF THE THUS FORMED CHLORIDE OF THE ALKYLCYCLOPENTANE IN THE PRESENCE OFTHE SULFURIC ACID WHILE MAINTAINING A HYDROGEN CHLORIDE PARTIAL PRESSUREOVER THE RESULTING REACTION MIXTURE AT ABOVE 0.1 ATMOSPHER UNTIL ASUBSTANTIAL AMOUNT OF DICYCLIC CHLORIDE IS FORMED, THEN STOPPING THEREACTION AND RECOVERING AS THE REACTION PRODUCT A MIXTURE COMPRISINGPRINCIPALLY THE DICYCLIC CHLORIDE AND A DICYCLIC HYDROCARBON FORMED BYCONDENSATION OF THE CHLORIDE OF THE ALKYL CYCLOPENTANE.